1. Field of Invention
The present invention relates AC electrical power which provides energy to homes and businesses. More particularly, it relates to a device and method for creating micro interruptions or micro pulsing of current in an alternating current power supply which provides the current and RMS voltage to an attached inductive or resistive or combination load being energized by the power supply. The device and method herein, by interrupting the current flow in a plurality of micro second interruptions yielding substantially equal total interrupted durations on both sides of an AC duty cycle effectively lowers the actual amount of power consumed by household and business electrical devices, while concurrently being invisible to such devices and allowing them operate within normal parameters and without damage thereto. The disclosed device in some current preferred embodiments also provides the ability to monitor and maintain individual power circuits of a home or business using individual breakers communicating with a central monitoring system. In such an embodiment the device allows for the customization of the power on individual circuits to match the load and to reduce power consumption individually on each circuit as well as monitor that circuit for malfunctions. Still further, the device and method herein disclosed and described, provides a means for power factor correction in AC circuits which ultimately will result in power savings and a more stable power grid wherein voltage current offset is a factor.
2. Prior Art
The United States and the industrialized world operate in this modern era through the use of a plethora of electrical devices which provide both controllable living environments and machines and devices which enhance and multiply the work output of the average person. Such electrical devices are conventionally powered by alternating current (AC) electrical through a building electrical system communicating electrical power from a local power grid supplying power from a generating utility device through wires, junction boxes, and electrical sockets conveniently located in the various rooms and on the external structure of businesses and homes.
In homes using conventional AC power, devices such as computers, televisions, refrigerators, air conditioners, heating devices, and untold numbers of other electrical devices, increase comfort levels and productivity. Businesses, in the same fashion, use AC power for computers, machinery, pumps, lighting, motors, and environmental heating and cooling devices as well as thousands of other devices powered by alternating current to increase the productivity of workers as well as provide a controlled environment in which workers operate.
Most such businesses and residences provide the electrical current to power the various electrical consuming devices through a plurality of circuits formed of wires which extend from a main junction box which communicates AC power from a connection to a utility grid through a plurality of circuit breakers to the individual circuits. Connection to the electrical devices to the circuit is conventionally achieved by a plug on the electrical device being inserted into a socket communicating with the individual electrical circuit. In the case of devices with a large current draw, such as air conditioners and electrical motors and other appliances requiring substantial electrical current, a permanent wired connection through a junction box may be required. The majority of electrical devices powered by alternating current from a central power grid are connected in this fashion and operate very well.
Commonly, electrical power provided by power generating companies is in the form of alternating current which in the United States alternates at a rate of 120 cycles per second or 60 Hz and in many foreign countries at the rate of 100 cycles per second or at a rate of 50 Hz. Unlike a direct current (DC) flow of electricity through a circuit that has a constant current directional flow and a constant magnitude of that current flow, an alternating current has neither a constant direction nor constant magnitude. Since alternating current flows back and forth in a circuit it has no direction, but the number of oscillations of current flow in the circuit does produce a frequency which is a component of determining the effective current in the circuit. The current (I) available in an AC circuit to provide power to run a component is generally determined as I=Imax Sin 2π FT where F equals the frequency and T equals time.
For a 60 Hz supply, used in the United States and many countries, the current builds up to a maximum in one direction and then drops to zero in the first 1/120th of a second. The current then builds up to a peak in the opposite direction and again drops to zero in the next 1/120th of a second, making 1/60th of a second for the entire cycle. A light bulb or an electric heating element being a resistive load works equally well whichever way the current is flowing, and so do AC electric motors. Many foreign countries use a 50 Hz timing of the oscillations.
Most appliances and electronic devices used in home and business of industrialized nations have come to depend on a this constant frequency of the electrical current and use this alternation for timing purposes of the device itself or in the case of motors to actually produce the magnetic fields that turn the motor itself. This is especially true in the case of appliances and machinery using induction electrical motors which depend on the AC current being constant during cycles and oscillating at an appropriate rate. Consequently, any electrical power conservation device and method that is to be used in conjunction with AC power in conventional home and business electric devices must be invisible to the device using the provided timing or frequency of the electrical current such that the electrical device “sees” a properly timed oscillation of the provided current and therefor operate in normal parameters based on the current alternation.
Conventionally used “dimmers” frequently are not actually saving any energy as many simply use a resistor which is placed in the circuit with the light being dimmed to absorb current that would otherwise be available to the light. Newer style dimmers and power conservation devices function to chop or create a single timed large void or interruption in the current flow for a single defined period of time during one of the current cycles of an oscillation. What is effectively accomplished by this large void in current is that the maximum current available is lowered for the single duration in once cycle of each oscillation thereby lowering the current available to the device in the circuit. The output frequency is thus quite different from the input frequency. The longer the void created in the current cycle, the less current is available to the attached device, however the greater the interruption in the timing and the greater the difference between the output frequency and input frequency.
However, such devices in chopping a single segment from one side of the current cycle play havoc with electrically powered devices which depend upon the continuing and constant oscillation of the current cycle providing a timer to the attached device. Computers and induction motors and similar devices seeking the constant 60 Hz or 50 Hz cycles of line current are seriously impaired for function when a large portion of one cycle is void of electrical current. Some devices may even falsely sense that the current is reversing if the segment of current void for a sufficient time increment, thus disabling the device or even causing damage to the circuits when the current restarts.
Another serious problem arises in the use of induction style AC electric motors which are major energy consumers and thus a major target for electrical energy conservation. Such motors function by positioning windings about the armature that are spaced to take advantage of the constant timed 60 Hz or 50 Hz oscillation of the AC current supplied and the substantially equal output frequency and input frequency of the circuit. While many such motors use an auxiliary stationary winding to start the armature turning, once the desired armature speed is reached only the windings maintain the armature in the desired and proper rotation. If a conventional current interruption device such as a dimmer is inserted into the circuit providing power to an induction motor, the device only interrupts the current flow from one segment of one oscillation, or interrupts for too large a portion in both segments. This current interruption throws the current frequency out of balance and plays havoc with the fields formed inside the motor by the windings since they are spaced to take advantage of the 60 Hz or 50 Hz frequency in generating the fields around the armature. Interrupting the current flow in a single segment section during one oscillation collapses the magnetic field during the time that the current is interrupted and either throws the motor out of balance causing erratic rotation, overheating, and eventual failure of the device. Lengthening the interruption as is conventionally done with light bulb dimmers to lower the output, further increases the damage done to the running of the induction motor by further collapsing the magnetic fields and throwing the device out of balance. This is why users are warned not to place conventional dimmers in the circuit with motors or other devices that depend on a constant frequency of the AC current to function.
Still further, in using electronic devices such as computers and televisions and sound equipment and the like, industry and consumers have gone to great lengths to insure a constant and totally uninterrupted power supply even adding components to the circuit to clean up the power fluctuations. Such components generally monitor the AC current cycles for certain intervals during the output frequency and input frequency and should an interruption be sensed, the devices use batteries or other current storage devices generate a current to fill the void. Consequently conventional dimmer style current interruption devices will not function upstream in the power suppled in such a circuit since the subsequent device downstream in the circuit tries to undo the interruption of current which the dimmer chops from one side of the AC oscillation.
The device disclosed herein provides a significant saving in power consumption and solves the problems of AC current interruption causing damage to components. The disclosed device also provides great ability to manage AC power communicated to a single device or to an entire house or building using a plurality of short micro interruptions of the current flow during both phases of the current oscillation of an AC line current. By interrupting the current for a plurality of micro second segments for a substantially aggregate equal amount of time on sides of the oscillation in a complete one second or otherwise timed AC cycle, the perceived output frequency from the disclosed device sensed by the attached AC electrical device is maintained substantially the same as the input frequency and the effective current and the RMS voltage, provided to, and used, by a circuit or component, is lowered. However, unlike conventional power chopping devices which interrupt the current for a single longer or shorter period on one oscillation of a frequency cycle, the disclosed device micro chops the current, and does so for a substantially equal total duration and substantially equal number of micro second durations on both oscillations of each cycle. The result being that the AC output frequency “seen” by the attached electrical device is substantially equal to the AC input frequency but the effective current provided and the RMS voltage is reduced. Due to the micro second durations of the current interruption, and the fact that both sides of each AC cycle are substantially equally interrupted with micro interruptions yielding substantially the same aggregate duration of interruption, the interruptions are invisible to the attached device. The AC device in the U.S. requiring a normal 60 Hz frequency rate thus functions normally but uses less electrical current and at a lower RMS voltage. Even devices such as electrical line conditioners or uninterruptible power supplies, which sample the current and frequency of the AC oscillation to ascertain voltage and frequency, do not see the interruptions since there is a plurality of short micro second interruptions in the current flow which are generally faster than the sampling rate, and, the interruptions occur on both the output and return sides of the circuit to yield substantially equal aggregate amounts of current interrupted on both sides of the oscillation of the AC current during the one second duty cycle.
The current best mode features a switching means capable of making current interruptions which are micro seconds in duration, occurring in a range from 10 to 100 times on each cycle with one half of the interruptions being on the negative oscillation and one half being on the positive oscillation each individual AC current cycle. Such micro second interruptions can be made in both single and multiple phase AC power supplies such as the conventional three phase power supplies used by large motors. One current preferred mode features fifty such micro chopping current interruptions per cycle however this may be adjusted in the aforementioned range depending on the current and voltage requirements of the circuit. Since each complete cycle of a conventional 60 Hz AC circuit used in the United States takes only one second, the duration of each of the twenty-five interruptions on both oscillations is extremely short. Further, since there are so many short interruptions, lengthening or shortening each interruption varies the effective maximum current available to the circuit widely without causing the devices attached to sense an end to the negative or positive oscillation of the cycle. As such, the device and method can vary the length and number of the micro interruptions of current to yield the RMS voltage and current required to run the load placed on the circuit being served by the device. A very short relative increase in current interruption time on each of the 50 such interruptions will thus combine to yield a larger total aggregate effect on the maximum available current. Conversely, a small adjustment to shorten the interruptions yields a substantial adjustment to increase the aggregate total of current available. The result being a highly adjustable circuit which allows attached electrical devices to function in normal parameters with the minimum required current and RMS voltage to achieve that function once the circuit output is adjusted.
Of course the system in the current best mode interrupts the current flow for micro seconds on both sides of the current flow of the conventional AC circuit to yield the best and most transparent current flow reduction and the best control on the system for varying loads added or subtracted from the circuit. However it is envisioned that some may not need such a balanced system that is invisible to the load and it is anticipated that a reduction in power usage could be obtained micro chopping only one half of the oscillation when used only on resistive loads such as a light dimmer and such is anticipated. However, the current best mode of the device features substantially equal total duration of current interruption through substantially equal numbers of micro interruptions in the current flow on each side of one AC current cycle.
The effective current available to the circuit using the disclosed device can be static and non adjustable in the simplest form of the device by simply programming the number and duration of timed micro-interruptions to achieve the desired static output of current and RMS voltage to the device or devices attached to the output side of the device. In this simple form, a switching means capable of handling the amount of line current and the and making the extremely short interruptions would be used and timed or controlled at a set pace to yield the desired current and line voltage on the output side. This embodiment might be used when the device is placed on an AC motor or in front of a single attached device downstream on an AC circuit. Or, as in the current best mode, the output current to the load on the circuit and returning current when the flow is reversed, may be monitored and the durations and/or number of micro interruptions in the current flow provided by the switching means may be increased or decreased as needed by for operation of attached devices to the circuit being monitored. This circuit monitoring can be accomplished by a feed back circuit communicating with one of the wires on the output side of the switching device and with a timer and/or computer controller which controls the number, and/or duration, of the micro interruptions in each oscillation of the AC cycle through a constant communication with the switching means which cuts or interrupts the current flow in the circuit. If less current and effective RMS voltage is needed by the attached electrical device, then the number and/or duration of the interruptions of current flow would be increased by a command to the switching devices. Should more current and effective or RMS voltage be required by the attached device, then the number and/or duration of the interruptions would be decreased. If the attached electrical device requires an especially clean power supply, the number of micro interruptions can be increased and shortened to a point where the interruptions of current are invisible to the electrical device but still using less power.
As noted, by interrupting each oscillation of the current, a substantially equal number of times, for substantially equal micro second durations, thereby yielding a substantially equal aggregate amount of current interruption, the interruptions are essentially invisible to the attached device since no “reversal” of current is sensed by the attached device as would be the case where one or a few very long interruptions occur in the current.
The disclosed device works equally well when inserted into three phase and other multi phase versions of AC power supplies.
Consequently using the disclosed device and method, computers, induction motors, and other device which are very sensitive to current oscillation and assuming a current reversal at a defined period of time of interruption, only sense the lower current and effective voltage available from the output side of the device and thus function otherwise within normal parameters.
U.S. Pat. No. 4,616,301 (Small) teaches a switching power supply for converting an input voltage to a different output voltage. However, Smith teaches a constant pulse or current interruption duration and varying the frequency of the line output and requires a power transformer and chokes to accomplish the task. This makes the device bulky and yields the potential of damage to frequency specific devices such as induction motors and computers.
As such, there exists a need for an easily manufactured device which may be readily inserted into a single or multiple phase AC circuit of a home or business and reduce the power consumption of the attached electrical components. Such a device should be invisible to the electrical components attached to the circuit, or be adjustable to achieve such, and must maintain the component perceived line output frequency to avoid malfunction or damage to the attached electrical components. Such a device in more sophisticated embodiments should provide constant monitoring of the circuits in which it is inserted, provide the minimum current to the load on the circuit to function normally, and constantly adjust to any changes in the load of the circuit. Also, in the more sophisticated embodiments, such a device should have a means to eliminate residual energy from the circuit during the periods of current interruption. Additionally, such a device should be able to function as both circuit breaker and circuit monitor providing real time analysis and telemetry regarding the usage and function or malfunction of the individual circuits in which the device functions. Still further, such a device should be capable of not only providing energy savings, but to also provide a means of power factor correction in AC circuits which may be inefficient due to inductive loads.